Biomedical subjects

Laurie K Brown

Publications and source records attributed to Laurie K Brown.

3 recordsLinked to original sources

PubMed2004

Intraocular lens power calculation after incisional and thermal keratorefractive surgery.

PURPOSE: To evaluate the efficacy of corneal topography in determining the central corneal refractive power in intraocular lens (IOL) power calculations after incisional and thermal keratorefractive surgery. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This retrospective review comprised 20 eyes (14 patients) that had cataract extraction with IOL implantation or refractive lens exchange after radial keratotomy, hexagonal keratotomy, or laser thermal keratoplasty. The effective refractive power (EffRP) of the Holladay Diagnostic Summary on the EyeSys Corneal Analysis System was used to determine the central corneal refractive power, which was input into the Holladay 2 IOL calculation formula. RESULTS: Eighty percent of eyes achieved a postoperative spherical equivalent refraction within +/-0.50 diopter of emmetropia. CONCLUSION: The use of the EffRP increases the likelihood of an acceptable refractive outcome after cataract or refractive lens exchange surgery in eyes with a history of keratorefractive surgery.

Cataract Extraction↗

PubMed2002

Immersion A-scan compared with partial coherence interferometry: outcomes analysis.

PURPOSE: To compare 2 methods of axial length measurement, immersion ultrasonography and partial coherence interferometry, and to elucidate surgical outcomes based on immersion measurements. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: Axial length measurements in 50 cataractous eyes were obtained by optical biometry (IOLMaster, Zeiss Humphrey Systems) and immersion ultrasound (Axis II, Quantel Medical), and the results were compared. Intraocular lens (IOL) power calculations in the same eyes after cataract extraction and posterior chamber IOL implantation were evaluated retrospectively based on the postoperative spherical equivalent prediction error. RESULTS: Immersion ultrasonography and partial coherence interferometry measurements correlated in a highly positive manner (correlation coefficient = 0.996). Outcomes analysis demonstrated 92.0% of eyes were within +/-0.5 diopter of emmetropia based on immersion axial length measurements. CONCLUSION: Immersion ultrasonography provided highly accurate axial length measurements and permitted highly accurate IOL power calculations.

Biometry↗

PubMed2002

Comparison of sonic and ultrasonic phacoemulsification using the Staar Sonic Wave system.

PURPOSE: To compare the performance of sonic phacoemulsification with that of ultrasonic phacoemulsification in regard to 1-day postoperative visual acuity, corneal edema, and procedure efficiency. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This prospective nonrandomized study comprised 86 eyes with mild to moderate nuclear sclerotic cataract. Forty-three eyes had sonic and 43 ultrasonic phacoemulsification using the Staar Sonic Wave phacoemulsification system. The mean age was 76 years in the ultrasonic group and 71 years in the sonic group. The mean nuclear sclerosis was 2.0+ in the sonic group and 1.9+ in the ultrasonic group. Patient age, lens density, postoperative corneal edema, 1-day postoperative uncorrected visual acuity (UCVA), and the percentage of eyes with a visual acuity of 20/40 or better were determined. In addition, the mean ultrasonic and sonic times, mean percentage phaco power, and mean effective phaco time (EPT) were calculated in each group. RESULTS: Both groups had a 5% incidence of trace corneal edema. The mean UCVA was 20/41 in the ultrasonic group and 20/42 in the sonic group. Seventy-nine percent of eyes in the ultrasonic group and 74% in the sonic group had a UCVA of 20/40. The mean percentage phaco power was 7.2% and 7.6% in the ultrasonic group and sonic group, respectively. The mean EPT was low in both groups, 4.0 and 2.9 seconds, respectively. CONCLUSION: Sonic technology yielded outcomes similar to those of ultrasonic phacoemulsification with respect to postoperative visual acuity and corneal edema in patients with average density nuclear sclerotic cataract.

Corneal Edema↗